The broad aim of this research is to further our understanding of the organization of striate cortex. Receptive fields will be mapped for cells in the striate cortex of cats and kittens, and these same cells will be stained intracellularly with a Procion dye. This technique makes it possible to correlate the physiological and histological properties of a single cell. In the course of this study, many purely extracellular recordings will be obtained, and these will be used to test hypotheses about the organization of striate cortex into functional columns, and the specificity of cortical cells for stimuli moving in a preferred direction. The data obtained from this study will be used to test key assumptions and predictions of a model of the development striate cortex under the influence of perinatal visual experience.